The traditional method of surgery involves creating an incision in a patient large enough so that the surgeon can work with and handle directly the patient's organs and tissues. Unfortunately, this traditional method carries with it a relatively high risk of infection due to the exceptional amount of exposure to which the patient's internal organs and tissues are subjected during the surgery. Other significant drawbacks associated with traditional methods of surgery are the length of recovery time required for a patient and the significant pain suffered by the patient because of the size of the incision.
These negative effects of surgical treatment were significantly mitigated by the introduction of endoscopic surgery. Endoscopic surgery generally involves making one or more relatively small incisions in a patient and then inserting one or more small surgical tools. The surgical tools are generally mounted on one end of a long, thin element having on the other end a handle and a means for actuating or manipulating the surgical tool. The endoscopic surgical tools are often also outfitted with optical and light-delivery channels so that the surgeon can view the area of the surgery.
While the advent of endoscopic surgical techniques significantly reduced the drawbacks of traditional surgical techniques, endoscopic surgery still involves a relatively high risk of infection, a relatively long recovery period, and significant pain for the patient. Recently, these negative effects have been even further reduced by the introduction of transgastric and transluminal endoscopic surgery.
In transgastric surgery, for example, an endoscopic instrument is inserted into the patient's mouth and fed to the patient's stomach. The wall of the patient's stomach can then be punctured so that the instrument can access other parts of the patient's abdomen. An incision in the wall of the stomach is preferable to external incisions because there are no nerve endings in the stomach. Transgastric endoscopic surgery reduces patient pain and recovery time as well as the risk of infection.
An endoscopic instrument that is inserted into the patient for transgastric or transluminal surgery generally includes one or more surgical tools, an optical channel, one or more light channels, and/or one or more channels for evacuation or insufflation. The endoscopic instruments preferably have other unique features. A full description of the functioning of a transgastric/transluminal surgical apparatus can be found in commonly owned U.S. application Ser. No. 11/739,833, the disclosure of which is incorporated by reference herein. First, transgastric/transluminal surgical apparatuses preferably are designed such that insertion into the patient's body is easy and causes the patient a minimum of trauma. Second, the endoscopic instrument preferably provides a means for multiple surgical tools to be used to exert force or perform functions in multiple directions at the surgical site. This is more difficult in transgastric and transluminal surgery because there is only one possible angle of approach since the surgical tools are preferably inserted in the same place, for example, the patient's mouth. In conventional endoscopic surgery on the other hand, surgical tools can be inserted into multiple incisions at multiple locations in the abdomen so that the surgeon has an advantageous ‘working triangle.’ The working triangle allows the surgeon to exert force in multiple directions and therefore better perform surgical tasks. In transgastric and transluminal surgery, it is more difficult to create this working triangle since the surgical tools are inserted parallel to one another.
In general, an endoscopic surgical instrument for use in transgastric, transluminal, or similar surgical techniques has a handle portion, an elongated middle portion, and a tool portion. The handle and tool portion are located on opposite ends of the middle portion, such that when the instrument is inserted into a patient, the tool portion is directed to the surgical site inside the patient's body while the handle remains outside the patient's body so that the surgeon may control the tool portion. The handle generally includes mechanisms for actuating the tool portion of the surgical instrument. There are many types of tool portions of surgical instruments which may be used in this way, for example, grasping jaws, clippers, scissors, and the like.
Once endoscopic surgical instruments are present at a surgical site, whether in a transgastric, transluminal, or other setting, it is necessary that the surgeon have the ability to precisely control or steer the surgical instruments. The tool portions should be capable of easy movement around the surgical site. Indeed, one of the most critical components of an effective and safe surgical operation is the ability of the surgeon to efficiently perform the desired surgical tasks. For this reason, the surgeon must be able to move the tool portions in a precise manner with as little restriction on the movement of the tool portion as possible.
There are many endoscopic surgical instruments in the prior art which are intended to provide a surgeon with as much control over the tool portion as possible. For example, U.S. Pat. No. 5,318,528 to Heaven et al. discloses a steerable surgical device having an inner tubular member and an outer tubular member. The tubular members are disposed coaxially and are rotatable relative to one another. At least one of the tubular members is pre-bent at its distal end. When both tubular members are pre-bent, the distal end can be steered by rotating the tubular members relative to one another, so that the distal end is moved from between about a 90° configuration to a straight configuration relative to the axis of the tubular members. The configuration, or overall bend, of the distal end is changed as a result of the varying force of the pre-bent sections of the tubular members on each other as the tubular members are rotated. A surgical tool is mounted on a distal end of the inner tubular member and is operated by control wires.
Unfortunately, this design has significant drawbacks. For example, due to the fact that some flexibility is required in the tubular members at their distal end to change the configuration or overall bend of the distal end, the distal end is susceptible to unwanted flexing when a force is applied to the end. If a surgeon desires to exert a pulling or pushing force on a patient's body tissue, the device disclosed in Heaven et al. may not retain the desired curvature at its distal end. Such a situation introduces imprecision and uncertainty into the surgical procedure.
U.S. Pat. No. 5,921,915 to Aznoian et al. discloses a surgical instrument having a flexible body insertion tube and a tubular member having a sheath and forceps jaws (or other surgical instrument) attached at a distal end. The tubular member is disposed inside and slideable within the sheath, which is relatively stiff. The tubular member has at least one resilient bend near its distal end such that when the tubular member is forced out of the end of the sheath, the surgical instrument on the distal end will be deflected away from the axis of the sheath. The tubular member may be rotated about its longitudinal axis.
The surgical instrument disclosed in Aznoian et al. also suffers from significant drawbacks. First, due to the flexible nature of the tubular member, it may also flex in an undesirable manner when the surgeon exerts a pulling or pushing force with the tubular member. Second, the amount of control that a surgeon has over the distal end of the tubular member is limited because the amount of bend is fixed by the resilient bend. While the amount of bend may be controlled somewhat by the degree to which the distal end is protruded from the sheath, this amount of control over the surgical tool may not be adequate for some applications. Finally, actuation of the instrument's functions is complicated, such that it would require two hands to control the longitudinal displacement of the tubular member and the rotation of the tubular member.
U.S. Pat. No. 5,766,196 to Griffiths discloses a medical instrument with a steerable distal end attached to an elongated middle section which is in turn attached to a handle assembly. A surgical tool is mounted at the tip of the distal end. Control wires run from a steering knob located on the handle assembly through the middle section to the steerable distal end. The steerable distal end is comprised of stacked, disc-shaped elements which have holes for receiving the control wires, a central cavity, and two cut out portions which form a projection. The distal end is steered by tensioning the control wires such that the disc-shaped elements rock about their projections in unison. The distal end is therefore moveable in a plane to either side of the longitudinal axis of the elongated middle section. The distal end is rotatable into any desired angular position. A control and restraining mechanism holds the control wires and therefore the steerable section in a position selected by the surgeon.
The medical instrument disclosed in Griffiths also suffers from notable drawbacks. While the distal end allows articulation, the middle section to which the distal end is attached is a rigid, elongated member. The fact that the middle section is rigid limits the usefulness of the device in certain endoscopic surgery techniques. Particularly, transgastric and transluminal surgery require that the tools employed have at least some flexibility. Second, articulation of the distal end and actuation of the surgical tool would require use of two hands for accurate control.
What is needed, therefore, is an endoscopic surgical instrument that gives a surgeon precise control over the position of a surgical tool at a surgical site. The instrument should be employable and useful in a wide variety of surgical techniques. The instrument should also be simple and efficient to operate. It is also important that the instrument be easy to clean and sterilize. The instrument should also be simple to manufacture.